The present invention relates to an apparatus and method for determining proper appliance size. In particular, the present invention relates to an apparatus and method for determining appliance size wherein appliance on time and total time that the appliance is monitored are recorded.
Whenever a major appliance is purchased, substantial cost savings can be realized by buying an appliance sized such that its capacity is fully utilized at peak energy demand conditions. This is true whether the appliance be a gas furnace, an oil furnace, an electric furnace, an electric air conditioner, etc. While a preferred embodiment of the present invention is generally disclosed hereafter in terms of sizing gas furnaces, it will be appreciated that the present invention may be utilized with any number of different types of appliances. Further, in addition to other uses, the present invention can be used on an existing appliance to determine if the existing appliance's capacity is being fully utilized or is sufficient for peak demand. In addition, the present invention can be used to determine the proper size of a replacement appliance for the currently existing appliance. Proper sizing of an appliance reduces purchase, maintenance and energy costs, as well as conserves energy.
Recently, high efficiency furnaces such as pulse type furnaces have gained wide acceptance because of their relatively high efficiency. As a result, consumers are in increasing numbers replacing their conventional furnaces with a high efficiency type furnace. There is a tendency to install oversized furnaces, thereby impacting the savings in fuel and costs which would normally be achievable. Therefore, a simple, inexpensive and yet accurate apparatus and method is needed for sizing furnaces, particularly where an existing furnace is being replaced with a new furnace.
There has been a long history of heat loss and heat gain calculations. However, most of these are rather lengthy, complicated and at best, an educated guess as to the amount of equipment or furnace size necessary to offset the heat loss or heat gain of a building. Further, such calculations are consistently on the strong side, indicating equipment larger than needed. This leads to oversized equipment which does not produce the comfort required, and because of cycling losses and short inefficient burns, is expensive to operate. Short cycling will also contribute to shortened equipment life because of strain caused by starting and stopping.
The advent of the high efficiency furnace, recently introduced to the general public, has dramatically brought to light the fact that an oversized furnace is an expensive furnace to operate. As a result, crude methods of calculations have emerged. Many of these consist of recording actual BTUH input to heating equipment by referring to extremely cold periods. By taking the total energy input for a specified length of time, typically in days, and dividing the input by the number of days times 24 hours per day, a crude estimate of the heat requirement can be obtained. Because it is difficult to separate and allocate the amount of energy required by water heaters, dryers, cooking, etc. this method is often inaccurate and further doubted by potential furnace purchasers. Furthermore, it is rather inconvenient to conduct such monitoring activity during extremely cold weather. Additionally, such testing is often not possible during the warm summer months. Another significant factor often overlooked is the fact that during the day there is solar gain which provides for internal heat gain so as to falsify the actual energy requirements of the building.
The present invention solves these and many other problems.